Sed & awk (2nd Edition)

Sed & awk (2nd Edition)

Arnold Robbins, Dale Dougherty


sed & awk describes textual content processing courses which are mainstays of the UNIX programmer's toolbox.

sed is a "stream editor" for enhancing streams of textual content that would be too huge to edit as a unmarried dossier, or that may be generated at the fly as a part of a bigger info processing step. the most typical operation performed with sed is substitution, changing one block of textual content with another.

awk is a whole programming language. in contrast to many traditional languages, awk is "data driven" -- you specify what sort of info you have an interest in and the operations to be played while that facts is came upon. awk does many stuff for you, together with instantly beginning and shutting information documents, studying files, breaking the files up into fields, and counting the documents. whereas awk presents the positive aspects of most normal programming languages, additionally it is a few unconventional good points, equivalent to prolonged standard expression matching and associative arrays. sed & awk describes either courses intimately and features a bankruptcy of instance sed and awk scripts.

This version covers good points of sed and awk which are mandated by way of the POSIX general. This such a lot significantly impacts awk, the place POSIX standardized a brand new variable, CONVFMT, and new capabilities, toupper() and tolower(). The CONVFMT variable specifies the conversion layout to exploit while changing numbers to strings (awk used to exploit OFMT for this purpose). The toupper() and tolower() features every one take a (presumably combined case) string argument and go back a brand new model of the string with all letters translated to the corresponding case.

In addition, this version covers GNU sed, newly on hand because the first variation. It additionally updates the 1st version insurance of Bell Labs nawk and GNU awk (gawk), covers mawk, an extra freely to be had implementation of awk, and in short discusses 3 advertisement models of awk, MKS awk, Thompson Automation awk (tawk), and Videosoft (VSAwk).

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